Q: I’ve seen some new guitar pedals, such as the Pigtronix Quantum Time Modulator, that require 18-volt power supplies (as opposed to the 9-volt supplies used by most pedals). Why do they use higher voltage than other pedals?
A: In the case of the Quantum and many other stompboxes, the reason for the 18-volt power supply is to allow for higher headroom within the pedal. This helps to maintain a clean sound no matter how hot the input signal is. In some cases, pedals are designed to accept either 9-volt or 18-volt power supplies, allowing for the choice of the amount of headroom in the pedal.
